Hi Javier!
This is such a big accomplishment – congratulations on getting your first Airbnb listing up and running! It sounds like you've poured a lot of heart and hard work into renovating the property, and that definitely shows.
To have Zero artistic abilities you did a great job! People are drawn to beautiful and well-lit spaces on Airbnb and you hit the nail on the head with what you did. I would definitely stay here.
Your solution with the locked bedroom for longer stays is clever! It allows you to comply with regulations while still offering the space for larger groups on extended visits. You might want to mention this strategy clearly in your listing description, so it's transparent to potential guests.
It's good that you're open to feedback! Don't be nervous – you've clearly put a lot of thought and effort into this.
Congratulations again, I hope your first listing is a big success.